The present invention relates to a walk-on platform arrangement comprising at least a first sub-platform, which is movable from a rest position in a direction of extension into a working position, and a second sub-platform, which in the working position is disposed behind the first sub-platform, wherein a rear boundary edge of the first sub-platform and a front boundary edge of the second sub-platform in the rest position are spaced vertically apart from one another.
Such platform arrangements are known from prior art.
In particular, such platform arrangements are known, which comprise gratings and are used in automated zones of spray booths in vehicle body lacquering installations to provide a walk-on platform for maintenance purposes, whereas the sub-platforms of said known walk-on platform arrangements in the rest position are pushed together in such a way that the sub-platforms lie one above the other.
A drawback of the known walk-on platform arrangements is however that in the working position of the respective platform arrangement steps are formed between the sub-platforms and pose an accident risk because an operative walking on the platform arrangement for maintenance purposes may stumble over such a step and sustain a serious injury.
The object of the present invention is therefore to provide a walk-on platform arrangement of the type described above, which reduces the risk of accident for an operative walking on the platform arrangement in the working position.
In an example embodiment of a walk-on platform arrangement in accordance with the invention, at least a first sub-platform, which is movable from a rest position in a direction of extension into a working position, and a second sub-platform, which in the working position is disposed behind the first sub-platform are provided. A rear boundary edge of the first sub-platform and a front boundary edge of the second sub-platform in the rest position are spaced vertically apart from one another. A guide system is provided, by means of which the relative motion between the first sub-platform and the second sub-platform as the first sub-platform moves into the working position is guided in such a way that the vertical distance between the rear boundary edge of the first sub-platform and the front boundary edge of the second sub-platform in the working position is smaller than in the rest position.
In accordance with the concept according to the invention the height of the step, which arises between the two sub-platforms in the working position of the platform arrangement, is reduced compared to the known platform arrangements so that the risk of an operative stumbling or tripping over such a step while walking on the platform arrangement is markedly reduced.
Simply bevelling the front edge of the more elevated sub-platform would not have the desired effect because, particularly in spray booths of a vehicle body lacquering installation, the gratings of the platform arrangement are highly greased so that at bevelled points of the platform arrangement there would be a considerable danger of slipping, with the result that the accident risk would be increased rather than reduced.
It is particularly advantageous when the guide system is designed in such a way that the vertical distance between the rear boundary edge of the first sub-platform and the front boundary edge of the second sub-platform in the working position is smaller than the thickness of the second sub-platform. It is thereby guaranteed that the height of the step formed in the working position between the two sub-platforms is smaller than the thickness of the more elevated sub-platform, with the result that at such a step the foot of an operative may not pass below the more elevated second sub-platform and therefore get caught on the second sub-platform. This substantially reduces the accident risk compared to a platform arrangement, in which the step height is greater than the thickness of the more elevated sub-platform so that the foot of an operative may pass below the more elevated sub-platform.
In a preferred embodiment, it is provided that the guide system is designed in such a way that the vertical distance between the rear boundary edge of the first sub-platform and the front boundary edge of the second sub-platform in the working position is substantially zero. As a result, there is substantially no step at all formed between the two sub-platforms in the working position so that along the point of separation between the two sub-platforms there is no substantially greater risk of accident than at other points of the platform arrangement.
In principle, for realization of the platform arrangement according to the invention any relative motion between the two sub-platforms may be considered, which results in the vertical distance between the rear boundary edge of the first sub-platform and the front boundary edge of the second sub-platform in the working position being reduced compared to the rest position.
For example, it might therefore be provided that the guide system is designed in such a way that the rear boundary edge of the first sub-platform is raised as the first sub-platform moves into the working position.
In a preferred construction of the platform arrangement according to the invention it is however provided that the guide system is designed in such a way that the front boundary edge of the second sub-platform is lowered as the first sub-platform moves into the working position.
As yet no detailed information has been provided about the construction of the guide system.
It may therefore be provided that the guide system comprises at least one first guide element disposed on the one sub-platform, preferably at least two first guide elements disposed on the one sub-platform, and at least one second guide element disposed on the other sub-platform, preferably at least two second guide elements disposed on the other sub-platform.
In particular, it may be provided that the first guide element takes the form of a guideway, along which the second guide element is guided.
In a particularly simple construction of the platform arrangement according to the invention, the guideway comprises a substantially even rest portion and a deflection portion directed obliquely relative to the rest portion. By virtue of the deflection of the second guide element in the deflection portion of the guideway it is easily guaranteed that the two sub-platforms move in the desired manner relative to one another.
In the present case it has proved particularly successful when the deflection portion is inclined at an angle of approximately 20xc2x0 to approximately 60xc2x0, preferably at an angle of approximately 40xc2x0 to approximately 50xc2x0, relative to the even rest portion of the guideway.
To limit the maximum relative displacement of the two sub-platforms in the direction of extension, it may be provided that the guideway comprises a stop region for limiting the movement of the second guide element relative to the guideway.
It may further be provided that the first guide element comprises a receiving region for receiving the second guide element in the working position. The effect achieved thereby is that the position of the first guide element in the working position is well defined and the sub-platforms of the platform arrangement in the working position are not accidentally displaced relative to one another, which might endanger an operative walking on the platform arrangement.
In a preferred refinement of the platform arrangement according to the invention, it is provided that the second guide element comprises at least one roller. By virtue of the rolling of said roller along a first guide element in the form of a guideway, the two sub-platforms in the course of extension into the working position are guided relative to one another with very low friction.
The required relative motion in vertical direction between the rear boundary edge of the first sub-platform and the front boundary edge of the second sub-platform may be realized in a simple manner in that the first sub-platform and/or the second sub-platform is capable of swivelling about a substantially horizontal swivelling axis.
It is further advantageous when the sub-platforms comprise in each case a supporting frame for receiving at least one grating. Such, mostly rectangular gratings are obtainable as standard components, with the result that such a sub-platform comprising gratings is particularly easy and inexpensive to manufacture.
A sub-platform formed at least partially by gratings is moreover easy to clean.
In principle, the platform arrangement according to the invention may be formed by two sub-platforms, which in the working position are disposed one behind the other.
However, if the walk-on platform arrangement is to have as large a walk-on surface as possible in the working position and yet take up only a small amount of space in the rest position, it is advantageous when the platform arrangement comprises at least one third sub-platform, which in the working position is disposed behind the second sub-platform, wherein in the rest position a rear boundary edge of the second sub-platform and a front boundary edge of the third sub-platform are spaced vertically apart from one another and the platform arrangement comprises a guide system, by means of which the relative motion between the second sub-platform and the third sub-platform as the second sub-platform moves into the working position is guided in such a way that the vertical distance between the rear boundary edge of the second sub-platform and the front boundary edge of the third sub-platform in the working position is smaller than in the rest position.
In said manner the height of the step, which is formed in the working position between the second and third sub-platform, is reduced or even brought totally to zero in order to lessen the risk of accident. In said case, the same concept is applied as has already been described above for reducing the step height between the first sub-platform and the second sub-platform.
The concept according to the invention may be extended in a corresponding manner to include platform arrangements having any desired number of sub-platforms.
The walk-on platform arrangement according to the invention is particularly suitable for use in an installation for lacquering workpieces, in particular vehicle bodies, which comprises a conveying apparatus for conveying the workpieces through the installation and a walk-on platform arrangement, wherein the platform arrangement runs in longitudinal direction of the conveying apparatus and has a direction of extension aligned transversely, preferably at right angles to the longitudinal direction of the conveying apparatus. An operative may walk on said walk-on platform arrangement in the working position in order to service the conveying apparatus, while the sub-platforms of the walk-on platform arrangement in the rest position are spaced apart from the conveying apparatus in the direction of extension so that the sub-platforms in the rest position are situated outside the operative range of the lacquering installation, in which the workpieces are lacquered, and are therefore soiled with lacquer mist only slightly or not at all.
Further features and advantages of the invention are the subject matter of the following description and graphic representation of embodiments.